The present invention relates to an external method for employing control display navigation unit (CDNU) in trainer system, which allows a CDNU, loaded with an actual Operational Flight Program (OFP), to function properly in a flight simulator environment of a trainer system without sacrificing the trainer-unique functions that are unique to the flight simulator operation.
This invention provides a method to apply a CDNU (control display navigation unit) in a flight simulator environment provided by a trainer system. Originally, the CDNU with an operational flight program OFP was used in the aircraft to control the navigation and communication equipment. Usually, to use the CDNU in the trainer system, the OFP must be modified to an operational trainer program OTP in order to address the trainer-unique functions. The OFP modification or the development of an OTP for each version of each platform is an arduous and costly job.
FIG. 2 depicts the CDNU application in the real flight environment. In the aircraft, the CDNUs 11, 12 are used to control the real navigation and communication equipment. The CDNUs 11, 12 reduce aircraft complexity through integrated control of navigation, communications, and other avionics equipment using a multiplex data bus. The CDNU provides centralized control of all interfaced avionics systems 40.
The software loaded into the CDNU defines its function. The program that is loaded into the unit during manufacture or in the field is referred to as Operational Flight Program (OFP). This software program determines the function of the CDNU. Multiplex data bus messages are defined by the OFP to transmit data between the CDNU and the real avionics equipment 40.
FIG. 3 depicts the CDNU used in the trainer system 30. In the trainer system 30, the navigation and communication equipment is emulated by the simulation computer. The CDNUs 11, 12 are connected to the simulation computer through the multiplex data bus. The actual CDNU is used in the simulator in order to take advantage of the CDNU processing capability. However, a problem arises in the flight simulator, because the system is not in a real flight. Since the CDNU software is designed to operate in the real aircraft environment, several anomalies occur when it is used in the flight simulator environment. The CDNUs 11, 12 can not adapt to some of the trainer-unique functions, such as initialization/reset, freeze, run, slew, snapshot and present position calculation, which are unique to the flight simulator operation. During execution of the trainer-unique functions, the simulator stops emulating the real avionics equipment and requesting extra information from the CDNUs. The CDNU/OFP cannot handle these situations. Modification of the OFP is therefore required. The OFP is modified to an Operational Training Program (OTP) that can address the trainer-unique functions and a set of multiplex data bus messages are defined by the OTP to transmit data between the CDNUs 11, 12 and the trainer system 30 during the trainer-unique functions.
As an example, let us discuss a situation to address a trainer-unique function, Snapshot. In the helicopter training, the pilot is often required to repeat a specific training period or the instructor needs to show a specific period that the pilot has experienced for instruction purpose. To realize this function, all the state data and the training system experience must be saved for later use. A CDNU/OFP does not have this function. During the repeated training, the CDNU also needs to show the repeated process to the pilot.
Each aircraft platform that uses the CDNU has aircraft-specific software installed in that CDNUxe2x80x94the Operational Flight Program (OFP). Currently, each OFP is being modified for each flight simulator, on a case-by-case basis, to address trainer-unique functions. The present training simulator is implemented using the CDNU OTP integrated into the CDNU/OFP of each aircraft to provide the functionality to recognize an external computer that is used for aircrew training. The modification of the OFP for each flight simulator is a tedious and costly job, and must be repeated each time the OFP design changes. In summary, the problems of the existing OTP include the following.
1. OFP needs to be modified to function as the OTP.
2. OFP needs to be modified for each type of aircraft. Therefore each simulator needs a different OTP.
3. Each time the version of OFP changes, the corresponding OTP must be modified. It is costly and laborious.
It is an objective of the present invention to provide an external method for employing CDNU in trainer system that allows the CDNU, loaded with OFP, to function properly in a simulator environment and provide the trainer-unique functions.
It is another objective of the present invention to provide a CDNU Trainer Interface Unit (CTWU) adapted to connect between the CDNU and the trainer system for processing the external method for employing CDNU in trainer system so as to allow the CDNU/OFP to function properly in a flight simulator environment and provide the trainer-unique functions.
It is another objective of the present invention to provide an external method for employing CDNU in trainer system by connecting the CTIU between the CDNU and the trainer system, wherein the CTIU can be implemented by commercial-off-the-shelf (COTS) modules based on an open standard bus structure.
It is a further objective of the present invention to provide a CTIU which uses OFP and OTP pre-defined multiplex data bus messages to communicate with the CDNU/OFP and the trainer system respectively.
It is a further objective of the present invention to provide a CTIU which must provide functions to simulate real avionics equipment with respect to the CDNU/OFP.
It is a further objective of the present invention to provide a CTIU which must provide functions to simulate a CDNU with OTP with respect to the trainer system.
It is, a further objective of the present invention to provide an external method for employing CDNU in trainer system, wherein during normal simulation mode, the CTIU acts as a message relay between the CDNU/OFP and trainer system.
It is a further objective of the present invention to provide a CTIU that can provide proper data for both the CDNU/OFP and the trainer system during the trainer-unique functions.
It is another objective of the present invention to provide a CTIU which comprises a computer with two pairs of multiplex data bus controllers. It is serially integrated between the CDNU and the remaining trainer system. The CTIU will communicate with both the trainer system and the CDNU/OFP. With CTIU, there is no need to modify the OFP to address the trainer unique functions. The functions of the Operational Training Program (OTP) will be realized by the CTIU to the CDNU. The CTIU activates OTP-equivalent capabilities upon receipt of OTP active commands from the trainer system. The trainer-unique functions will be performed by the CITU to the CDNU. There will be no need to modify the OFP and/or integrate OTP functions into the CDNU.
It is also an objective of the present invention to provide a CTIU connected between the CDNU and the trainer system. The CTIU communicates with both the trainer system and the CDNU/OFP, using two sets of multiplex data buses. To the CDNU/OFP, the CTIU acts like the real navigation and communication systems. To the trainer system, the CTIU acts like a CDNU with OTP. The CTIU will be able to address the trainer-unique functions with no modification to the OFP and CDNU hardware. The functions of the Operational Training Program (OTP) will be realized by the CTIU to the CDNU/OFP. The CTIU activates OTP-equivalent capabilities upon receipt of OTP active commands from the trainer system.
In order to replace the trainer-unique functions realized by the CDNU with OTP, the CDNU Trainer Interface Unit must emulate the trainer-unique functions in two directions:
(1) With respect to the trainer system, the CTIU must transfer all the data required by the trainer system during the trainer-unique functions, acting like a CDNU with OTP.
(2) With respect to the CDNU/OFP, the CTIU must act like the real navigation and communication equipment. During the normal simulation mode, the navigation and communication equipment is simulated by the trainer system. The Interface Unit connects between the CDNU/OFP and trainer system and relays the simulated messages from the trainer system. During the trainer-unique function mode, the CTIU must provide the data required by the CDNU/OFP.
(3) With respect to the pilots, the CDNU/OFP must allow them to deal with the Trainer-unique operations, under the control of the CTIU.